1. Field of the Invention
This invention relates to polymeric adhesive compositions and their use in laminates, and particularly photographic elements and processes to obtain a desirable combination of properties. In particular, this invention relates to heat-activatable, water-soluble adhesive compositions capable of bonding hydrophilic surfaces to hydrophobic surfaces in photographic materials. A preferred embodiment of this invention is the use of certain anionic iminodisulfonyl group-containing polymeric adhesives in image transfer film units.
2. Description of the Prior Art
It is well known that certain condensation polymers are useful as adhesives. For instance, U.S. Pat. No. 3,546,008 of Shields et al, issued Dec. 8, 1970 and British Pat. No. 1,237,671 of Kibler et al, published June 30, 1971, disclose water-dissipatable polyesters containing sulfonate salt groups which are useful as sizing and adhesive compositions for textile fibers. Other water-dissipatable or -soluble adhesive compositions containing sulfonate salt groups are described in U.S. Pat. Nos. 3,563,942 of Heiberger, issued Feb. 16, 1971 (in laminates); 3,734,874 of Kibler et al, issued May 22, 1973 (in packaging materials); 3,779,993 of Kibler et al, issued Dec. 18,1973 (in packaging materials); and 3,853,820 of Vachon, issued Dec. 10, 1974 (in textile fibers).
Jackson et al, in U.S. Pat. No. 3,515,628, issued June 2, 1970, disclose highly crystalline condensation polymers made of various mixtures of diols and diacids, particularly phthalic acid derivatives, which are useful as adhesives for metal can seams. Price et al, in U.S. Pat. No 3,700,644 issued Oct. 24, 1972, disclose polyester fibers having an aromatic sulfonamide moiety.
Various condensation and addition polymeric adhesives useful in photographic materials are well known, as disclosed in U.S. Pat. Nos. 2,698,243 of Bachelder et al, issued Dec. 28, 1954; 3,056,491 of Campbell, issued Oct. 2, 1962; 3,256,090 of Booth, issued June 14, 1966; 3,309,201 of Friedman et al, issued Mar. 14, 1967; 3,376,265 of Yokouchi et al, issued Apr. 2, 1968, and 3,511,659 of Dennis et al, issued May 12, 1970.
French Pat. No. 1,593,118, published July 3, 1970 describes a method of making polyesters useful as synthetic textile fibers comprising an anionic iminodisulfonyl moiety. No use of these polyesters as adhesives is disclosed.
Organic solvent-soluble polyesters comprising an acid component made with 1 to 15 mole percent of a diacid containing anionic iminodisulfonyl moieties are disclosed in U.S. Pat. No. 3,546,180 of Caldwell et al, issued Dec. 8, 1970. These polyesters are useful as synthetic textile fibers or as adhesives and films if mixed with small amounts of water-insoluble crosslinked polymers.
Arcesi et al, in U.S. Pat. No. 3,929,489, issued Dec. 30, 1975, describe light sensitive polyesters comprising a diol component which may include 1,4-bis(2-hydroxyethoxy)cyclohexane; and a diacid component comprising from 2 to 45 mole percent of anionic iminodisulfohyl units and up to 55 mole percent of a light sensitive crosslinkable diacid. These polyesters are soluble in organic solvents and aqueous alcoholic alkaline developers and are used in photographic elements such as lithographic printing plates and photoresists. These polyesters are insoluble in distilled water. No use as adhesives in silver halide photographic materials is disclosed.
Image-transfer or diffusion transfer processes are well known in the art. Various formats for color diffusion transfer assemblages are described in U.S. Pat. Nos. 2,352,014 of Root, issued June 20, 1944; 2,543,181 of Land, issued Feb. 27, 1951; 2,983,606 of Rogers, issued May 9, 1961; 3,020,155 of Yackel et al, issued Feb. 6, 1962; 3,227,550 of Whitmore et al, issued Jan. 4, 1966; 3,227,552 of Whitmore, issued Jan. 4, 1966; 3,415,644; 3,415,645; and 3,415,646 all of Land, all issued Dec. 10, 1968; and 3,635,707 of Cole, issued Jan. 18, 1972; Canadian Pat. Nos. 674,082 of Whitmore, issued Nov. 12, 1963 and 928,559 of Cole, issued June 19, 1973; U.S. Pat. Nos. 3,362,819 of Land, issued Jan. 9, 1968; 3,362,821 of Land, issued Jan. 9, 1968; 3,647,437 of Land, issued Mar. 7, 1972; and 3,765,815 of Schlein et al, issued Sept. 4, 1973; Belgian Pat. Nos. 757,959 and 757,960; British Pat. Nos. 904,364 and 840,731; and copending U.S. application Ser. No. 676,945 of Hannie, filed Apr. 14, 1976. None of these references teach or suggest the adhesive compositions disclosed herein or their use in photographic materials.
In these formats, the image-receiving layer containing the photographic image for viewing can be separated from the photographic layers after processing or, in some embodiments, it can remain permanently attached and integral with the image-generating and ancillary layers present in the structure when a transparent support is employed on the viewing side of the assemblage. The image is formed by color-providing substances released from the image-generating units, diffusing through the layers of the structure to the dye image-receiving layer. After exposure of the assemblage, an alkaline processing composition permeates the various layers to initiate development of the exposed photosensitive silver halide emulsion layers. The emulsion layers are developed in proportion to the extent of the respective exposures, and the color-providing materials which are formed or released in the respective image-generating layers begin to diffuse throughout the structure. At least a portion of the imagewise distributed or released color-providing substances migrate to the dye image-receiving layer to form an image of the original subject.
Typically, adhesives are used in image transfer units to bond supports, subbed or unsubbed, to cover sheets or other layers around the edges of the units. Adhesives can also be used to bond subbing layers to supports or cover sheets; photosensitive layers to image-receiving layers; photosensitive layers to cover sheets; and the like. In bonding photosensitive layers to cover sheets and to image-receiving layers, it is sometimes helpful to use masks or spacer rails to separate the layers. The adhesive may then be used to bond the masks over the spacer rail with the layer of the film unit to be bonded.
Most adhesives taught in the art exhibit extremely low binding strengths at elevated temperatures, such as within the range of 50.degree. C. to 90.degree. C. Hence, they must be used at low temperatures, undesirably limiting manufacturing and processing conditions. Further, these prior art adhesives do not satisfactorily bond all types of materials. For instance, some can be used only to bond hydrophilic surfaces, others adhere only to hydrophobic surfaces. Still further, most adhesives known in the art are water-insoluble and must be coated with organic solvents and hardened with drying. These organic solvents are substantially more costly and more burdensome to dispose of after use than aqueous solutions, since, if untreated, they can be ecologically objectionable.
It is evident, then, that there is a need in the photographic arts for water-soluble, heat-activatable adhesives having high bonding strengths over a wide range of temperatures.